It has become popular in bars, taverns, restaurants, and similar establishments to serve ice cold shots of various liquors and spirits. As a result, a need has developed for an apparatus that can efficiently and effectively meet such cooling objectives. It is desirable that the spirits be cooled to a temperature far below the freezing temperature of water and insufficient quantity to meet a continuous demand without interruption.
The obvious way to attempt to meet this need is to store receptacles containing spirits in a conventional freezer away from the bar. The problem with using such freezers is that it is difficult and dangerous for personnel who serve spirits to handle the receptacles that are cooled to temperatures well below the freezing point of water. Furthermore, constant removal of these receptacles from such freezers causes the temperature of the spirits to increase or remain in flux. Also, for marketing reasons, it is desirable to display bottles at or behind the bar.
One attempt to improve the conventional freezer is a cooling dispenser known as the "Cool Shots.TM." by Cool Shots Inc. In this device, the bottle itself is not cooled, but a small amount of beverage flows into a cooling chamber. The "Cool Shots.TM." device, however, can dispense only one shot (1-11/2 ounces) at a time because it chills only a small volume of spirits at a time. The next shot of spirits or liquors must wait to be chilled.
Thermoelectric coolers are generally known in the art for other applications, typically, to cool drinking water, or other soft drinks. For example, as discussed in U.S. Pat. No. 4,913,713, a thermoelectric cooling device or "chips" operates as a solid state heat pump. The cold junction of the chip absorbs or removes heat from a cold surface, while the hot junction of the chip pumps heat to a heat sink. The rate of heating or cooling is directly proportional to the direct current passing through the chip, and if the current is reversed the cold junction will be hot while the hot junction will be cold. It is also important to prevent moisture from contacting the chip to ensure proper operation of the chip. Thermoelectric chips may be made by using two elements of semi-conductors, such as Bismuth Telluride doped to create either an excess (N-type) or deficiency (P-type) of electrons. Thermoelectric cooling chips are commercially available from a variety of sources including MELCOR, Materials Electronic Products Corp. of Trenton, N.J.
The coolers taught by the '713 patent and related U.S. Pat. No. 4,866,945 were specifically designed for cooling a 21/2 gallon jug of water. The coolers were not designed to chill water to anywhere near the freezing point of water, and thus only have to bring the water temperature down to approximately 50.degree. F. or to temperatures suitable for drinking. U.S. Pat. Nos. 4,133,456, 4,311,017 and 4,274,262 similarly disclose thermo-electric coolers that do not anticipate chilling liquids to sub-freezing temperature range. Since the coolers taught in these references do not bring the liquids down to sub-freezing temperatures, these references do not address the problem of thermal contraction of the heat transfer and cooling elements, or the efficiency required from the cooler to achieve such low temperature and therefore not useful for the prevent application. Therefore, these devices are not capable of withstanding the stress and strain of thermal contraction and expansion.
Thus, thee is a need for a cooler that is capable of cooling liquid to this desired low temperature and, in particular, a small bar-top cooler which is capable of continuously dispensing near zero degree individual drinks.